1. Field of the Invention
The present invention relates to the field of releasably securing PCI/AGP cards into their connectors within a computer. More particularly, the present invention relates a single hold down member that is quickly releasable, quickly re-secured, and capable of simultaneously securing a plurality of expansion cards within their respective connectors.
2. Description of the Prior Art
PCI/AGP cards, or xe2x80x9cexpansionxe2x80x9d cards are used by computers to interface with some external device. Common expansion cards include SCSI ports, serial ports, parallel ports, external drive ports, modems, and video cards. Because such expansion cards often allow coupling an external device to the expansion card, there is typically an opening in the computer chassis from within the computer to outside the computer. When no expansion card is installed, a protective cover, typically sheet metal, covers the opening. This protective cover serves a variety of functions, including the prevention of electromagnetic noise from escaping the chassis, the prevention of dust and debris from accumulating within the computer, and shielding the electronic componentry from outside objects, and protecting consumers from electrical shock through contact with exposed componentry. FIG. 1 schematically illustrates protective metal covers 100 adjacent to the connectors 104 in which expansion cards are electrically coupled to an electronic system, such as a personal computer. The metal covers 100 typically comprise a flange 108 for engaging a surface of a chassis (not shown) in the usual manner. The flange 108 typically includes a slot 102 or screw hole where a screw 106 secures an individual cover 100 to the computer chassis.
FIG. 2 shows an expansion card 204 mounted in a connector 206. A protective cover 202 dimensionally similar to the protective cover 100 of FIG. 1 is coupled with the expansion card 204, thereby forming a face piece 202 of the expansion card 204. The protective cover or face piece 202 comprises a flange 212 and an upright member 214. Like the protective covers 100 used in shielding an unused slot, the face piece 202 of an expansion card 204 is typically made from sheet metal. Again, it is noted that the expansion card is secured by means of a screw 210 inserted through a hole or slot 208 in the flange 212 of the face piece 202.
Prior art uses of metal covers 100 and expansion cards that include an integral metal face piece 202 suffered from a number of limitations. The process of installation and/or removing the such metal covers 100 and/or expansion cards 204 was labor intensive. An installer must loosen, remove and/or install screws 106, 200, 210. Such a practice undesirably increases the cost of manufacturing a computer system and also the cost of upgrading a system by adding an expansion card 204 in an after market improvement of the personal computer. These and other problems are exacerbated owing to the relative tiny size of the screw 106, 210.
The steps typically required in the installation of a screw according to the prior art is illustrated in FIG. 3. According to the step 302, the worker must locate the tiny screw among components in his work area. In an assembly line environment with a bowl of screws in front of a worker, this step may require minimal time or concentration. In a repair environment where numerous screws, nuts, washers and other components may be spread about a work area, the delay may run from several seconds to a minute or more. According to steps 304 and 306, the worker picks up the screw and orients it in his fingers. In the step 308, the worker lines up the screw with the hole or notch in which it is to be inserted. In the step 310, the screw is inserted into the hole. In the steps 312 and 314, the worker picks up the screw driver with his free hand and inserts it into the screw driver head. In the step 316, the screw is tightened into place. If the worker is installing a PCI/AGP card, as a result of the connector, the card may stand upright on its own during the installation of the screw. In the installation of a protective cover, the worker may have to secure the protective cover with a few fingers, while holding the screw with several more, and using the other hand to wield the screw driver.
For each computer, the delay involved in inserting a screw is multiplied by the number of slots that are being loosened or tightened to install, remove, replace or inspect expansion cards. When multiplied by the assembly or repair of millions of computers, this represents a significant amount of time and a corollary loss of profits. Moreover, unscrewing and tightening screws requires a proper tool, and proper lighting. Although this may not be a problem on an assembly line environment where a worker is equipped with proper tools, for consumers adding or replacing expansion cards at home, locating a screwdriver and proper lighting may take anywhere from several minutes to a trip to the hardware store. For factory workers and consumers alike, the prospect of dropping a screw into the computer simply exacerbates the delays, particularly if the screw is difficult to retrieve. Occasionally, damage to a mother board may result from attempts to retrieve a lost screw. Further, the repetitive action of unscrewing and screwing can also result in a repetitive motion injury to an installer.
An attempt to address some of the problems inherent in the prior art was made by Micron technology in the development of a hold-down mechanism for multiple PCI/AGP cards, illustrated in FIG. 4. A tension arm 402 made from a rigid and flexible material is attached to a press plate 408. Typically, the tension arm is made from a rigid and flexible material such as sheet metal. The tension arm includes a bent flanged tab 404 which includes a hole 412 and a thumb screw 414 for locking the tension arm 402 in place. When in place, a pressing plate 408 portion of the construction is advantageously positioned against a free edge of one or more PCI/AGP cards. The tension arm 402 is ideally flexed through compression, thereby securing the pressing plate 408 against PCI/AGP cards. For structural integrity, a rigid support member 406 typically couples the press plate 408 to the tension arm 402. The rigid support member 406 is seen to extend across the lateral front edge of the press plate 408, providing strength and rigidity to the press plate 408 when engaging PCI/AGP cards, as further illustrated in subsequent drawings. As can be seen from FIG. 4, the tension arm 404, rigid support member 406 and press plate 408 are advantageously constructed from a single sheet of metal, thereby minimizing costs associated with manufacturing. When the thumb screw 414 is loosened, releasing the tab 404 from the computer chassis, the hold-down 400 pivots around a fixed point as further illustrated below.
FIGS. 5A and 5B show the operation of the Micron hold-down mechanism for securing multiple PCI/AGP cards. In FIG. 5A the Micron hold-down 400 is seen swivelled to the release position. In the released position, a user may remove and install PCI/AGP cards 204 or protective covers 100. In FIG. 5B, the tab of the hold down 400 is secured to the computer chassis 602 by means of the thumb screw 414. When the thumb screw 414 is screwed into a threaded hole 606 in the computer chassis 602, the press plate 408 is pressed against the flange 212 of the face piece 202 on the PCI/AGP card 204, thereby holding the PCI/AGP card 204 securely in the connector 206.
Although the thumb-screw hold down afforded some advantages over the prior art in terms of speed, it nevertheless retains numerous shortcomings. For a thumb screw 414 to be useful, it typically must have a knurled or tooled finish around the outer diameter of screw head, providing a texture which allows a user to grip the screw head. Because of the quality of machining, a knurled thumb screw 414 is substantially more expensive than the cost of a cheaply manufactured screw 106, 200, 210 seen securing PCI/AGP cards in FIGS. 1 and 2. Another weakness with a thumb screw for securing a hold-down is that, as with individual screws, a thumb screw can be lost. This hazard can be reduced by utilizing a screw with a shoulder so that it cannot fall out. Again, however, this convenience is only achieved at the expense of more complex and costly designs on the thumb screw and tapped hole. A further limitation of a thumb screw type hold down is that the hole 606 in the computer chassis must be threaded to accommodate a thread of a thumb screw. Because the thumb screw must be configured to be reliably inserted and removed repeatedly, and in light of the force needed to tap a hole, which may be hard to generate by holding a thumb screw between a thumb and forefinger, a self tapping screw is generally impractical. However, preparing a pre-tapped hole during the manufacture of the chassis again increases costs in tooling and assembly. Yet another limitation of a thumb screw type hold down is the time required to rotate the thumb screw into and out of its threaded aperture. Screwing and unscrewing require multiple twists of the assembler""s fingers, delaying production time. This is particular true in examining FIGS. 5A and 5B. To begin the process an assembler would have to align the thumb screw 414 to the threaded aperture 412. This alignment can be even more difficult in light of the fact that the tension arm 402 should be under a certain amount of tension to securely hold the PCI/AGP cards. To impart this tension to the tension arm 402, the threaded hole 606 in the chassis would have to be slightly lower than the hole 412 in the tab 404, such that aligning the two holes imparts a slight tension on the tension arm 402. All of these factors contribute to a delay, in aligning and screwing in the thumb screw during the assembly process. A reduction in manufacturing time or expense of parts is desired for maintaining a competitive edge in the manufacture of personal computers.
There exists therefore a need for a method and apparatus for releasably securing a plurality of expansion cards simultaneously within their respective connectors, thereby avoiding the need for separate installation steps. There further exists a need for a method and apparatus that can secure a plurality of expansion cards that avoids the need for tooling or tapping threads into a computer chassis. There further exists a need for a method and apparatus for securing a plurality of expansion cards within their respective connectors that avoids the need for screws that can easily be lost or misplaced. There further exists a need for a method and apparatus for securing a plurality of expansion cards within their respective connectors that avoids the need of expensive knurled thumb screws. There further exists a need for a method and apparatus for securing a plurality of expansion cards within their respective connectors that avoids the expenditure of assembly time in aligning a screw with a threaded hole, and further eliminates the expenditure of assembly time devoted to performing the repetitive motion of screwing in a screw to perform installation. There further exists a need for a quick release multi-card securing device that can be manufactured and installed at low cost, thereby addressing a critical market concern of computer manufacturers.
The present invention discloses a method and apparatus for releasably securing a plurality of PCI/AGP cards simultaneously within their respective connectors, thereby avoiding the need for separate installation steps. The PCI/AGP cards can comprise SCSI ports, serial ports, parallel ports, external drive ports, modems, and video cards. It will be readily recognized that such expansion cards are not intended to limit the scope of this discussion. Rather, the invention is intended to contemplate rapid installation of any electronic circuit board. However, for simplicity of this disclosure, the invention is described in terms of PCI/AGP cards.
The present invention further discloses a method and apparatus for securing a plurality of PCI/AGP cards in a manner without the need for tooling or tapping threads into a computer chassis. The present invention further discloses a method and apparatus for securing a plurality of PCI/AGP cards within their respective connectors that avoids the need for screws that can easily be lost or misplaced. The present invention further discloses a method and apparatus for securing a plurality of PCI/AGP cards within their respective connectors that avoids the need of expensive knurled thumb screws. The present invention further discloses a method and apparatus for securing a plurality of PCI/AGP cards within their respective connectors that avoids the expenditure of assembly time in aligning a screw with a threaded hole, and further eliminates the expenditure of assembly time devoted to performing the repetitive motion of screwing in a screw to perform installation. The present invention further discloses a quick release multi-card securing device that can be manufactured and installed at low cost, thereby addressing a market concern of computer manufacturers.
A quick release hold-down mechanism releasably secures a plurality of components within a computer chassis. The components may variously include protective covers positioned to cover expansion slots, and PCI/AGP cards properly inserted in their respective connectors. The quick release hold-down mechanism comprises a press plate for exerting a force to hold the PCI/AGP card into its connector; a tension arm operatively coupled to the press plate for holding the press plate in place, and a locking indent in the tension arm. The locking indent is configured to engage the computer chassis when the quick release hold-down mechanism is in a secure position, such that the press plate is substantially positioned to exert a force on a surface of either a protective cover or of a PCI/AGP card properly seated within a connector. The tension arm comprises a material that is capable of deforming and restoring when the locking indent engages and disengages the computer chassis. The quick release hold down mechanism comprises a pivot member around which the press plate pivots.